include <stdlib.h> include “chunk.h” include “scanners.h”

bufsize_t _scan_at(bufsize_t (*scanner)(const unsigned char *), cmark_chunk *c, bufsize_t offset) {

bufsize_t res;
unsigned char *ptr = (unsigned char *)c->data;

if (ptr == NULL || offset > c->len) {
  return 0;
} else {
  unsigned char lim = ptr[c->len];

  ptr[c->len] = '\0';
  res = scanner(ptr + offset);
  ptr[c->len] = lim;
}

return res;

}

!re2c
re2c:define:YYCTYPE  = "unsigned char";
re2c:define:YYCURSOR = p;
re2c:define:YYMARKER = marker;
re2c:define:YYCTXMARKER = marker;
re2c:yyfill:enable = 0;

wordchar = [^\x00-\x20];

spacechar = [ \t\v\f\r\n];

reg_char     = [^\\()\x00-\x20];

escaped_char = [\\][!"#$%&'()*+,./:;<=>?@[\\\]^_`{|}~-];

tagname = [A-Za-z][A-Za-z0-9-]*;

blocktagname = 'address'|'article'|'aside'|'base'|'basefont'|'blockquote'|'body'|'caption'|'center'|'col'|'colgroup'|'dd'|'details'|'dialog'|'dir'|'div'|'dl'|'dt'|'fieldset'|'figcaption'|'figure'|'footer'|'form'|'frame'|'frameset'|'h1'|'h2'|'h3'|'h4'|'h5'|'h6'|'head'|'header'|'hr'|'html'|'iframe'|'legend'|'li'|'link'|'main'|'menu'|'menuitem'|'meta'|'nav'|'noframes'|'ol'|'optgroup'|'option'|'p'|'param'|'section'|'source'|'title'|'summary'|'table'|'tbody'|'td'|'tfoot'|'th'|'thead'|'title'|'tr'|'track'|'ul';

attributename = [a-zA-Z_:][a-zA-Z0-9:._-]*;

unquotedvalue = [^"'=<>`\x00]+;
singlequotedvalue = ['][^'\x00]*['];
doublequotedvalue = ["][^"\x00]*["];

attributevalue = unquotedvalue | singlequotedvalue | doublequotedvalue;

attributevaluespec = spacechar* [=] spacechar* attributevalue;

attribute = spacechar+ attributename attributevaluespec?;

opentag = tagname attribute* spacechar* [/]? [>];
closetag = [/] tagname spacechar* [>];

htmlcomment = "!---->" | ("!--" ([-]? [^\x00>-]) ([-]? [^\x00-])* "-->");

processinginstruction = "?" ([^?>\x00]+ | [?][^>\x00] | [>])* "?>";

declaration = "!" [A-Z]+ spacechar+ [^>\x00]* ">";

cdata = "![CDATA[" ([^\]\x00]+ | "]" [^\]\x00] | "]]" [^>\x00])* "]]>";

htmltag = opentag | closetag | htmlcomment | processinginstruction |
          declaration | cdata;

in_parens_nosp   = [(] (reg_char|escaped_char|[\\])* [)];

in_double_quotes = ["] (escaped_char|[^"\x00])* ["];
in_single_quotes = ['] (escaped_char|[^'\x00])* ['];
in_parens        = [(] (escaped_char|[^)\x00])* [)];

scheme           = [A-Za-z][A-Za-z0-9.+-]{1,31};

// Try to match a scheme including colon. bufsize_t _scan_scheme(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 scheme [:] { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match URI autolink after first <, returning number of chars matched. bufsize_t _scan_autolink_uri(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 scheme [:][^\x00-\x20<>]*[>]  { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match email autolink after first <, returning num of chars matched. bufsize_t _scan_autolink_email(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+
   [@]
   [a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?
   ([.][a-zA-Z0-9]([a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*
   [>] { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match an HTML tag after first <, returning num of chars matched. bufsize_t _scan_html_tag(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 htmltag { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to (liberally) match an HTML tag after first <, returning num of chars matched. bufsize_t _scan_liberal_html_tag(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [^\n\x00]+ [>] { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match an HTML block tag start line, returning // an integer code for the type of block (1-6, matching the spec). // #7 is handled by a separate function, below. bufsize_t _scan_html_block_start(const unsigned char *p) {

const unsigned char *marker = NULL;

/*!re2c

 [<] ('script'|'pre'|'style') (spacechar | [>]) { return 1; }
 '<!--' { return 2; }
 '<?' { return 3; }
 '<!' [A-Z] { return 4; }
 '<![CDATA[' { return 5; }
 [<] [/]? blocktagname (spacechar | [/]? [>])  { return 6; }
   { return 0; }
/

}

// Try to match an HTML block tag start line of type 7, returning // 7 if successful, 0 if not. bufsize_t _scan_html_block_start_7(const unsigned char *p) {

const unsigned char *marker = NULL;

/*!re2c

 [<] (opentag | closetag) [\t\n\f ]* [\r\n] { return 7; }
   { return 0; }
/

}

// Try to match an HTML block end line of type 1 bufsize_t _scan_html_block_end_1(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [^\n\x00]* [<] [/] ('script'|'pre'|'style') [>] { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match an HTML block end line of type 2 bufsize_t _scan_html_block_end_2(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [^\n\x00]* '-->' { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match an HTML block end line of type 3 bufsize_t _scan_html_block_end_3(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [^\n\x00]* '?>' { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match an HTML block end line of type 4 bufsize_t _scan_html_block_end_4(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [^\n\x00]* '>' { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match an HTML block end line of type 5 bufsize_t _scan_html_block_end_5(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [^\n\x00]* ']]>' { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Try to match a link title (in single quotes, in double quotes, or // in parentheses), returning number of chars matched. Allow one // level of internal nesting (quotes within quotes). bufsize_t _scan_link_title(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 ["] (escaped_char|[^"\x00])* ["]   { return (bufsize_t)(p - start); }
 ['] (escaped_char|[^'\x00])* ['] { return (bufsize_t)(p - start); }
 [(] (escaped_char|[^)\x00])* [)]  { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Match space characters, including newlines. bufsize_t _scan_spacechars(const unsigned char *p) {

const unsigned char *start = p; \

/*!re2c

 [ \t\v\f\r\n]+ { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Match ATX heading start. bufsize_t _scan_atx_heading_start(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [#]{1,6} ([ \t]+|[\r\n])  { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Match setext heading line. Return 1 for level-1 heading, // 2 for level-2, 0 for no match. bufsize_t _scan_setext_heading_line(const unsigned char *p) {

const unsigned char *marker = NULL;

/*!re2c

 [=]+ [ \t]* [\r\n] { return 1; }
 [-]+ [ \t]* [\r\n] { return 2; }
   { return 0; }
/

}

// Scan a thematic break line: “…three or more hyphens, asterisks, // or underscores on a line by themselves. If you wish, you may use // spaces between the hyphens or asterisks.” bufsize_t _scan_thematic_break(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 ([*][ \t]*){3,} [ \t]* [\r\n] { return (bufsize_t)(p - start); }
 ([_][ \t]*){3,} [ \t]* [\r\n] { return (bufsize_t)(p - start); }
 ([-][ \t]*){3,} [ \t]* [\r\n] { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Scan an opening code fence. bufsize_t _scan_open_code_fence(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [`]{3,} / [^`\r\n\x00]*[\r\n] { return (bufsize_t)(p - start); }
 [~]{3,} / [^~\r\n\x00]*[\r\n] { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Scan a closing code fence with length at least len. bufsize_t _scan_close_code_fence(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [`]{3,} / [ \t]*[\r\n] { return (bufsize_t)(p - start); }
 [~]{3,} / [ \t]*[\r\n] { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Scans an entity. // Returns number of chars matched. bufsize_t _scan_entity(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 [&] ([#] ([Xx][A-Fa-f0-9]{1,8}|[0-9]{1,8}) |[A-Za-z][A-Za-z0-9]{1,31} ) [;]
    { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Returns positive value if a URL begins in a way that is potentially // dangerous, with javascript:, vbscript:, file:, or data:, otherwise 0. bufsize_t _scan_dangerous_url(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 'data:image/' ('png'|'gif'|'jpeg'|'webp') { return 0; }
 'javascript:' | 'vbscript:' | 'file:' | 'data:' { return (bufsize_t)(p - start); }
   { return 0; }
/

}

// Scans a footnote definition opening. bufsize_t _scan_footnote_definition(const unsigned char *p) {

const unsigned char *marker = NULL;
const unsigned char *start = p;

/*!re2c

 '[^' ([^\] \r\n\x00\t]+) ']:' [ \t]* { return (bufsize_t)(p - start); }
   { return 0; }
/

}